The present invention relates to a superconducting energy storage device, and, more particularly, relates to a superconducting energy storage device which is favorable for storage of electric power in superconducting magnets in the form of magnetic energy.
Heretofore, two types of magnets have been investigated or used for conventional superconducting energy storage devices. One type is a solenoid system in which a solenoid-type superconducting magnet is used for energy storage as described in Special Issue "V, Energy Storage by means Superconducting Coil," the Journal of the Institute of Electrical Engineers of Japan, Vol. 101, No. 6, pp. 525-529, June, 1981. The other type is a toroidal system in which a toroidal-type superconducting magnet is used for energy storage as described in "The Business and Technology Daily News" issued Dec. 6, 1983. In both the descriptions of the solenoid and toroidal systems, the realization of the superconducting energy storage device has been discussed in view of costs on the premise that electromagnetic force generated by such a superconducting magnet is supported by a bed rock such as granite.
Because each of the conventional superconducting energy storage devices is provided on the premise that electromagnetic force generated by such a superconducting magnet used for energy storage must be supported by an external bed rock, the device cannot be located freely except in a place having such a firm bed rock. In the prior art, therefore, there has been a problem in that the conditions for location of the energy storage device have some limitations.
Recently, a hybrid magnet type superconducting energy storage device, in which a toroidal magnet and a solenoid magnet are used as a superconducting energy storage magnet so that central force generated by the toroidal magnet in the direction of the large radius can be canceled by hoop force generated by the solenoid magnet, has been disclosed in JP-A-No. 63-52401 application by the same inventor of this application.
The device of this type has however a problem in that a gap is formed in the contacting surface between the toroidal magnet and the solenoid magnet because the solenoid magnet is arranged to be in contact with the circular surface of the circular toroidal magnet.
Further, most of these conventional techniques merely relate to the arrangement and production of a single unit of a superconducting energy storage device. In other words, there is no discussion of the provision of a plurality of units.
Heretofore, there has been a tendency to form the superconducting energy storage device in a large-scale unit. Taking a power plant as an example, the output of kilowatts from the power plant is generated by a plurality of electric generators, not by a single electric generator. It is apparent from this fact that the superconducting energy storage device should also be separated into a plurality of units or devices.
A new problem arises in arrangement of a plurality of energy storage devices. Particularly, because a large number of energy storage devices are to be located in the vicinity of cities, the limitation in conditions of location of the energy storage device will be made more severe.